Pivoting action low profile sickle drive

ABSTRACT

The pivoting action sickle drive has a low profile allowing incorporation in or below a floor of a header of a plant cutting machine to allow passage of cut plant material thereabout. The drive includes a substantially flat rotatable input element, and a drive arm connected eccentric thereto for eccentric rotation along an epicyclical path. The arm extends to a connection with a pivot arm of a pivot element that connects to a knife arm that drives a sickle knife assembly, such that the pivot element, knife arm and knife assembly will be reciprocatingly driven by the eccentric rotation of the drive arm. A second drive can oppositely drive a second sickle knife assembly, such that opposite forces generated by the drives will cancel. The drives can be packaged in a forwardly tapered or curved enclosure, and the pivot elements can be correspondingly shaped to streamline the drives.

This application is the US National Stage for International Application No. PCT/US12/39749, filed on May 25, 2012, which itself is related to and claims the benefit of U.S. Provisional Application No. 61/491,002, filed May 27, 2011.

TECHNICAL FIELD

This invention relates generally to a drive for the sickle of a header of an agricultural cutting machine, such as a combine, windrower or other crop harvesting machine, or a mower, and more particularly, to a drive mechanism configurable to have only a pivotally rotating drive shaft extending upwardly from an upper enclosure thereof for connection to a knife head, and which is configured to have a profile shape when viewed from the side that tapers convergingly toward a forward end thereof, so as to be adapted to be disposed in or below a floor or pan of the header, to reduce interference with plant material flow.

BACKGROUND ART

The disclosure of U.S. Provisional Application No. 61/491,002, filed May 27, 2011, is hereby incorporated herein in its entirety by reference.

Sickles typically including cutter bars supporting a row of knives, have been used to cut plants, including, but not limited to, hay, grasses, small grains and the like, for many years. The knives are composed of a plurality of knife or sickle sections which are mounted in side by side relation forming an elongate metal knife assembly. The elongate knife assembly is normally supported so as to slide longitudinally along an elongate stationary bar that has forwardly projecting, spaced apart guards bolted to a structural beam. The knife assembly moves back and forth in a reciprocating movement to move the knives relative to the guards so that the leading knife edges of the knives cross over the guards or through slots in the guards. This produces a shearing or cutting action which severs plant stems and stalks or other material captured between the knives and the guards.

In a harvesting machine, such as a combine or windrower, the knife assembly and stationary bar are typically supported in connection with a cutting head or header, and are oriented so as to extend sidewardly along a forward edge portion of structure such as a floor or pan of the header, hereinafter sometimes referred to generally as the floor. The floor or pan defines the lower periphery of a cut crop or plant flow area, which can include conveying apparatus, such as one or more augers or belts, operable in cooperation with a reel in machines so equipped, for conveying the cut plant material and crops, for instance, to a feeder inlet of a combine or windrow forming apparatus of a windrower.

The knife assembly is driven reciprocatingly longitudinally by an oscillating drive, which can include, but is not limited to, an eccentric shaft on a rotating hub, a wobble drive, or a similar well known commercially available device. Such drives are typically located at the sides of the header, so as to drive the knife assembly from the end. This location is advantageous as it allows the driving point for the knife assembly to be in line with the stationary bar, provides clearances for removal of the knife assembly, and provides space for assembly of the drive. Disadvantages of the side location include that the header must include significant frame structure for supporting the drive and to withstand forces and vibrations generated thereby. The end structure or crop divider at the end of the header must also be relatively wide, to accommodate the drive and to direct adjacent standing crops therepast, and increasing the possibility of accidentally pushing down adjacent standing crops. Additionally, for headers utilizing two drives located on opposite sides of the header, it is usually desired to time the operation of the drives such that the forces and vibrations generated by the respective drives cancel one another. This typically involves relatively long mechanical drive lines connecting the two drives together, which is disadvantageous as it adds weight, cost and complexity.

A knife assembly, which will weigh from 35 to 38 pounds for a typical 20 foot wide header, typically must accelerate and decelerate two times per cycle as a result of the reciprocating movement. A typical speed for the knife assembly is up to about 16 hertz or cycles per second. Thus, it can be seen, the reciprocating motion at a high cycle per second generates high acceleration values and high deceleration values that in turn generate high forces on the structural components. These high forces can have at least two negative effects, vibration at the drive system that may be transmitted to other components of the machine, and fatigue failure of the structural components themselves. On larger headers, for instance, headers 30 feet wide and greater, two knife assemblies each equal to one-half the sideward extent of the header are often used.

Driving a knife assembly or assemblies of a header from a more central location, such as the center of the header, would provide several advantages compared to a side location. Notably among these advantages, the header structure would not be required to support heavy drive units on one or both sides, such that the structure of the header could be lighter. Long timing apparatus extending between the ends could also be eliminated. If the drive mechanism could be incorporated into a location that would not interrupt or require dividing crop or plant material flow through the crop flow area of the header, the normal crop flow of the header would not be significantly impacted. And, since the drives are not located in the ends, the end dividers can be made significantly thinner, such that the header can have a shorter overall width, would be more easily maneuverable in relation to adjacent standing crop, and danger of downing the adjacent standing crop would be reduced.

Reference Priepke U.S. Pat. Nos. 7,810,304; 7,805,919; 7,730,709; 7,520,118; and 7,401,458, and Bich U.S. Pat. No. 8,011,272, which demonstrate that a sickle drive or drives can be incorporated in or below the header floor to solve one or more of the problems set forth above in regard to end mounted drives and interruption of plant material flow in the crop flow area of the header.

What is sought is a sickle drive adapted to be incorporated into or below the floor of a header of a plant cutting or harvester to reduce interruption and splitting of plant material flow, and which overcomes one or more of the shortcomings and limitations set forth above.

SUMMARY OF THE INVENTION

What is disclosed is a sickle drive adapted to be incorporated into or below the floor of a header of a plant cutting or harvester to reduce interruption and splitting of plant material flow, and which overcomes one or more of the shortcomings and limitations set forth above.

According to a preferred aspect of the invention, the sickle drive is located at least largely in a generally flat cavity at least partially bounded by an enclosure, having a forward end, a rear end, an upper bounds and a lower bounds defining the cavity therebetween. The cavity has a forward region having a shape which tapers or curves upwardly toward the forward end such that a forward region of the cavity is smaller in vertical extent compared to a rear region thereof. A first input element is disposed in the cavity, preferably in an upper region of the cavity adjacent to the upper surface. The first input element has a disk shape and is supported for rotation about a generally upstanding first rotational axis. A first eccentric element is connected to the first input element for rotation eccentrically about the first rotational axis. The drive includes a first drive arm disposed in the cavity in generally horizontal coextensive relation to the first input element, e.g., below it, and having a first end and an opposite second end. The first end is connected to the eccentric element for rotation therewith eccentrically about the first rotational axis, the first drive arm extending laterally relative to the first rotational axis to the second end. The second end pivotally connects to a first pivot element disposed beside the first input element. The first pivot element is supported for rotation about a generally upstanding first pivotal axis, and has a first pivot arm that extends eccentrically from the pivotal axis to the drive arm. As a result, the eccentric rotation of the first eccentric element will cause the first drive arm to reciprocatingly pivot the first pivot element about the first pivotal axis in a limited manner of travel, preferably largely within the profile of the input element when viewed from above or below.

According to another preferred aspect of the invention, a first knife arm is mounted on the first pivot shaft above the enclosure and is configured for connecting to a first sickle knife assembly in a manner such that the pivotal movement of the first pivot element will reciprocatingly move the first sickle knife assembly sidewardly relative to the enclosure.

According to another preferred aspect of the invention, the input element, eccentric element and the drive arm are each relatively flat, and at least substantially vertically coextensive, for vertical compactness. A rotatable power source, which can be, for instance, a fluid or electric motor, drive shaft, belt drive, chain drive, or the like, can be connected in driving relation to the input element and mounted on the enclosure, and can have a low vertical profile or extent, such that the overall vertical profile of the drive will be minimal generally coextensive with the drive, such that the drive fits into a tapered forward region of a header, just rearward of the sickle.

According to still another preferred aspect of the invention, a second drive that will be substantially a mirror image of the first drive can oppositely drive a second sickle knife assembly, such that opposite forces generated by the drives will be canceled. As still another preferred aspect of the invention, the first drive and the second drive are connected together for joint rotation in opposite rotational directions.

The enclosure can fully contain the drive or drives, for instance, by including full upper and lower covers, or it can partially enclose the drive or drives, such that all or a portion of any of the elements are exposed. For instance, as a non-limiting example, the enclosure can include or be incorporated in or below the floor of a header of a plant cutting machine which will serve as a cover, with all or a portion of a bottom region of the drive or drives, or elements thereof, exposed to the ground below, essentially the frame of the header then generally defining the lower bounds of the cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary side view of a harvester including a header having pivoting action low profile sickle drives according to the invention;

FIG. 2 is an enlarged fragmentary side view of the header and sickle drives of the invention;

FIG. 3 is a front view of the harvester and header, showing the location of the sickle drives;

FIG. 4 is a fragmentary perspective view of the header, showing aspects of the sickle drives;

FIG. 5 is an enlarged side view showing aspects of the header, drives, and sickle;

FIG. 6 is a simplified schematic top view of the drives, illustrating internal elements thereof;

FIG. 7 is a simplified schematic side view of the drives, with an enclosure in dotted lines to show internal elements of one of the drives;

FIG. 8 is a simplified schematic top view of elements of one of the drives and a portion of the sickle, to illustrate a range of pivotal positions thereof;

FIG. 9A is a simplified schematic top view of elements of one of the drives illustrating a pivotal position thereof;

FIG. 9B is a simplified schematic top view of the elements of one of the drives illustrating another pivotal position thereof;

FIG. 9C is another simplified schematic top view of the elements of one of the drives illustrating another pivotal position thereof;

FIG. 9D is another simplified schematic top view of elements of one of the drives illustrating still another pivotal position thereof; and

FIG. 10 is a simplified schematic top view of the header including another embodiment of low profile pivoting action sickle drives according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to the drawings wherein preferred embodiments of the invention are shown, in FIGS. 1 through 5, a conventional, well known agricultural cutting machine, which is a combine 20, is shown including a header 22 having low profile pivoting action sickle drives 62A and 62B constructed and operable according to the teachings of the invention. Header 22 is shown supported in the conventional, well-known manner on a forward end 24 of combine 20, and is operable for cutting or severing crops such as, but not limited to, small grains such as wheat and soybeans, and inducting the severed crops into a feeder 26 for conveyance into combine 20 for threshing and cleaning, in the well known manner, as combine 20 moves forwardly over a field.

Header 22 includes a pan or floor 28 which is supported in desired proximity to the surface of the field during the harvesting operation, and an elongate, sidewardly extending sickle 30 along a forward edge portion 32 of floor 28, sickle 30 being operable for severing the plants or crop for induction into header 22, as will be explained. Header 22 additionally includes an elongate, sidewardly extending reel 34 disposed above sickle 30 and rotatable in a direction for facilitating induction of the severed plant material or crops into header 22. Here, header 22 is configured as a draper type, having a system of elongate, flat, sidewardly moving draper belts 36 and 38 having upwardly facing surfaces disposed just rearwardly of forward edge portion 32, operable in cooperation with reel 34 for conveying the severed plant material or crops toward an inlet opening of feeder 26 for induction into combine 20, in the well-known manner.

Referring more particularly to FIG. 3, sickle 30 extends in a sideward direction along the width of floor 28, between a first side edge portion 40 of the floor, and an opposite second side edge portion 42. Sickle 30 includes an elongate, sidewardly extending first cutter bar assembly 44, and an elongate, sidewardly extending second cutter bar assembly 46 extending in end to end relation to cutter bar assembly 44, cutter bar assemblies 44 and 46 being supported in substantially longitudinally aligned relation adjacent to forward edge portion 32 of floor 28.

Referring more particularly to FIGS. 4 and 5, cutter bar assemblies 44 and 46 each include a plurality of sidewardly facing aligned slots 48 through a sidewardly extending array of guards 50 which project forwardly from a stationary bar 52 at sidewardly spaced intervals therealong. Stationary bar 52 extends the length of sickle 30 just forwardly of forward edge portion 32 of floor 28, and guards 50 are mounted to bar 52 with fasteners 54. Bar 52, in turn, is mounted to a frame 56 of header 22 adjacent to forward edge portion 32 by fasteners 54, as best illustrated in FIG. 5. Each of cutter bar assemblies 44 and 46 supports an elongate knife assembly 58 for reciprocating longitudinal movement within slots 48, each knife assembly 58 including a row of knife sections including oppositely facing, angularly related knife edges 60 which, in conjunction with adjacent guards 50, effects a shearing or cutting action which severs plant stems and stalks or other material captured between the knives and the guards as the knife sections are reciprocatingly moved sidewardly, as denoted by arrow A in FIG. 4.

As noted above under the Background Art heading, it is desirable to reduce negative effects of the reciprocating sideward motion of knife assemblies 58, including, but not limited to, vibration, fatigue failure, and the like, and also the disadvantages of known structures for effecting the motion, including the need for substantial structure for supporting drive mechanisms on the sides of headers, the increased width of side dividers containing the mechanism, and apparatus for timing drive mechanisms located on opposite sides of a header.

Reduction of these negative effects and disadvantages is achieved according to the present invention by utilizing first and second pivoting action low profile sickle drives 62A and 62B of the teachings of the present invention, for reciprocatingly driving the respective knife assemblies 58. First and second sickle drives 62A and 62B are illustrated in FIG. 1 at a center location on header 22 between side edge portions 40 and 42, although it should be noted that it is contemplated that sickle drives 62A and 62B could alternatively be utilized at other locations on a header, and that multiple sickle drives 62 could be used at multiple locations on a header, as described and illustrated later herein.

First and second sickle drives 62A and 62B are illustrated as packaged together in a low profile common enclosure 64. Enclosure 64 is configured so as to be integrated into or beneath floor 28 of header 22, in, or just rearward of, forward edge portion 32, as best shown in FIG. 5, to facilitate both smooth flow of crop or plant material thereover, and also smooth passage over the ground surface 66 therebelow. In this latter capacity, it can be observed that enclosure 64 is desirably configured to have a tapered profile shape when viewed from the side, preferably including an upper cover 68, and a lower cover 70 to allow disassembly, and which extend generally convergingly toward a forward end 72 of the enclosure. Also preferably, the forward end of lower cover 70 will have an upwardly curving shape, to guide and facilitate the smooth passage over the ground surface and flow of plant material thereabout. It can be observed that forward edge portion 32 of floor 28 has an upwardly curved shape, which combined with the upwardly tapered or curved forward end of enclosure 64, provides header 22 with an overall wedge shaped leading edge profile, which again, facilitates the smooth flow over the ground and of plant material over the front edge of the header. Enclosure can be mounted in any suitable manner, such as by attachment with fasteners to frame or structural elements of header 22.

As shown, upper cover 68 of enclosure 64 is located below forward edge portion 32 of floor 28, which can comprise sheet metal or other suitable material, such that cut plant material will flow over the enclosure without contacting it. Alternatively, upper cover 68 can be integrated into floor 28. Enclosure 64 will be of cast and/or machined metal construction such as steel or aluminum, and upper and lower covers 68 and 70 can be joined together with suitable fasteners or the like. A skid plate 74 can be disposed below at least the forward end, for protection from wear and contact with hard objects such as rocks and the like that may be encountered during operation.

Each of first and second sickle drives 62A and 62B includes a knife arm 76 atop upper surface 68 of enclosure 64 and extending forwardly therefrom. Knife arms 76 pivotally connect to the knife assemblies 58, respectively, and are movable by the respective drive 62A or 62B in a sideward pivoting action that will translate via a pivoting relationship into the above described sideward reciprocating movement, as restrained by the guards 50. Knife arms 76 are preferably the only upwardly externally protruding elements of first and second drives 62A and 62B, the other elements being located within an internal cavity 78 of enclosure 64. Knife arms 76 also preferably project forwardly through slots 80 in forward edge portion 32, to minimize interruption of the plant material flow.

Referring also to FIGS. 6 and 7, the internal elements of first and second drives 62A and 62B other than knife arms 76 are disposed in side by side relation in an internal cavity 78 of enclosure 64. First and second drives 62A and 62B are each configured as an epicyclic arrangement, including a central rotatable input element, an eccentric element rotatable along an epicyclical orbit about the rotatable input element, and a pivoting drive arm moved by the eccentric element to pivot the knife arm in the side to side direction. More particularly, first drive 62A includes a rotatable first input element 82 supported in an upper region of cavity 78 for rotation about a generally upstanding first rotational axis 84. Drive 62A includes a first eccentric element 86 supported in cavity 78 below first input element 82 for rotation thereby in eccentric relation to first rotational axis 84 about a generally upstanding first eccentric axis 88 laterally offset relative to rotational axis 84, such that eccentric element 86 will follow an epicyclical path 90 about rotational axis 84. Drive 62A includes a first drive arm 92 disposed in cavity 78, having a first end 94 and an opposite second end 96. First end 94 is rotatably connected to eccentric element 86 for rotation therewith along epicyclical path 90 (FIG. 6) about first rotational axis 84. First drive arm 92 extends laterally relative to axis 84 from first end 94 to second end 96. Second end 96 pivotally connects to a pivot arm 98 connected eccentrically to a pivot shaft 100 of a first pivot element 102 supported for rotation about a generally upstanding first pivotal axis 104 therethrough. Pivot shaft 100 extends upwardly through an aperture 106 through upper cover 68 of enclosure 64 and fixedly connects to a knife arm 76, e.g., via a splined connection or the like.

In operation, rotation of first input element 82 as denoted by arrow R, will cause first eccentric element 86 to orbit eccentrically along epicyclical path 90. First end 94 of drive arm 92, because it is connected to first eccentric element 86, will also orbit about epicyclical path 90, while end 96, because it is pivotally connected to pivot arm 98, will only move along a limited arcuate path 108 about pivotal axis 104. Because knife arm 76 is fixedly connected to the upper end of pivot shaft 100, it will be limited in movement to a corresponding arcuate path 108A. Additionally, because the opposite end of knife arm 76 is connected to a knife assembly 58, knife assembly 58 will be reciprocatingly moved sidewardly an amount A (FIG. 4) relative to guards 50, to effect the plant cutting action.

Second drive 62B includes a rotatable second input element 110 supported in an upper region of cavity 78 for rotation about a generally upstanding second rotational axis 112, beside first input element 82. Drive 62B includes a second eccentric element 114 supported in cavity 78 below second input element 110 for rotation thereby in eccentric relation to second rotational axis 112 about a generally upstanding second eccentric axis 116 laterally offset relative to rotational axis 112, such that eccentric element 114 will follow an epicyclical orbital path 118 about rotational axis 112. Drive 62B includes a second drive arm 120 disposed in cavity 78, having a first end 122 and an opposite second end 124. First end 122 is rotatably connected to second eccentric element 114 for rotation therewith about second eccentric axis 116 in eccentric relation to, and about, second rotational axis 112. Second drive arm 120 extends laterally relative to axis 112 from first end 122 to second end 124. Second end 124 pivotally connects to a pivot arm 126 connected eccentrically to a pivot shaft 128 of a second pivot element 130 supported for rotation about a generally upstanding second pivotal axis 132 therethrough. Pivot shaft 128 extends upwardly through an aperture 134 through upper cover 68 of enclosure 64 and fixedly connects to a second knife arm 76, again via a splined connection or the like. Second drive 62B will essentially be a mirror image of first drive 62A.

Referring also to FIGS. 8 and 9A-D, in operation, in the same manner as for drive 62A, rotation of second input element 110 of drive 62B, as illustrated by arrow R, will cause second eccentric element 114 to orbit eccentrically along epicyclical path 118. First end 122 of second drive arm 120, because it is attached to eccentric element 114, will orbit along path 118 about rotational axis 112 while also rotating about eccentric axis 116. This, in combination with the ability of pivot arm 126 and pivot shaft 128 of element 130 to only pivot about pivotal axis 132, results in limited pivotal movement of second end 124 of drive arm 120 and pivot arm 126 along an arcuate path 136 about axis 132. In this regard, the connection of knife arm 76 to knife assembly 58 is preferably a pinned connection such that knife assembly 58, or that portion thereof in proximity to knife arm 76, will also move along the pivotal path, such that some limited fore and aft movement of the knife assembly will occur, as denoted by the distance B in FIG. 8. The relationship between the guards and knife assembly can be configured to allow this. Alternatively, the connection between the knife head and knife assembly can be configured, e.g., slotted connection, to allow some limited fore and aft relative movement, such that the knife assembly only moves sidewardly.

Referring particularly to FIGS. 9A-9D, four positions along epicyclical orbital path 118 about rotational axis 112, of eccentric element 114, eccentric axis 116 and first end 122 of drive arm 120 of drive 62B, resulting from rotation of input element 110 denoted by arrow R, are shown. Also shown are the resulting translated positions of drive arm 120, pivot arm 126, and the attached knife arm 76 about pivot axis 132, for the four positions. This will result in the attached knife assembly being reciprocatingly moved in the above described manner. Movements of corresponding components of drive 62A will be the mirror image of those shown for drive 62B.

It is desired to reciprocatingly move the two knife assemblies 58 simultaneously in opposite sideward directions. To achieve this, first and second drives 62A and 62B are preferably operated in opposite direction, in timed relation. This is preferably accomplished by jointly driving the drives in opposite rotational directions. In the preferred configuration shown, first and second input elements 82 and 110 are connected together via enmeshed gears 138 and 140 which extend therearound, respectively. Alternatively, input elements 82 and 110 could be connected together by a cogged belt, a timing shaft, or the like, and the eccentric axes 88 and 116 offset to provide opposite directional movements of drive arms 92 and 120.

To rotate input elements 82 and 110, a rotatable power source 142 or input is provided, which is preferably an electric or fluid motor, connected in driving relation to one of the input elements 82 or 110 via a gear arrangement 144 or the like. Alternatively, the power source could comprise a shaft, chain or belt drive, as desired. Here, power source 142 is mounted to housing 64 at a large acute angle to the forward direction. This enables accommodating power source 142 in a manner to provide a shorter overall fore and aft extent of the drives.

As a feature of the invention, to provide a relatively thin, flat overall package, input elements 82 and 110, eccentric elements 86 and 114, and drive arms 92 and 120 of drives 62A and 62B are each relatively flat, and the eccentric elements and drive arms are substantially vertically coextensive, to provide vertical compactness, such that drives 62A and 62B are adapted to be unobtrusively positioned below or in the front region of floor 28 of a header, such as header 22, to allow relatively unhindered plant material flow thereover. In this regard, input elements 82 and 110 are each preferably disk or platter shaped elements supported for rotation about axes 84 and 112, respectively by suitable bearings 146 (FIG. 7), the inner races of which are connected to enclosure 64 by threaded fasteners 148 which serve as mounting shafts. This configuration provides input elements 82 and 110 mass to serve as flywheels for the drives. Also, input elements 82 and 110 overlap or are horizontally coextensive with large portions of drive arms 92 and 120, respectively, to facilitate compactness.

Eccentric elements 86 and 114 are fixedly connected to the respective input elements 82 and 110 for rotation therewith. Drive arms 92 and 120 are mounted about the respective eccentric elements 86 and 114 via bearings for rotation thereabout, the eccentric elements and drive arms being held vertically together by threaded fasteners or the like. The opposite ends of arms 92 and 120 connect to pivot arms 98 and 126 via pivot joints 150 which can also include bearings to allow relative rotation or pivoting action. Pivot shafts 100 and 128 are supported for rotation in apertures 106 and 134, respectively, by bearings 152. Upper and lower covers 68 and 70 are fastened together by fasteners at spaced locations therearound. Power source 142 is also attached with fasteners. The splined portions of knife arms 76 and upper ends of pivot shafts 100 and 128, respectively, are held together by fasteners, in a clamping action.

Here, it should be noted that the knife arms of the drives of the invention can be oriented in a variety of directions other than the generally forward direction shown in FIGS. 6-8 and 9A-D. A representative different orientation is shown in FIG. 10, by sickle drives 62C and 62D, like parts of drives 62C and 62D, and drives 62A and 62B, being identified by like numbers. Drives 62C and 62D differ from drives 62A and 62B by the orientation of the drive arms in a more sidewardly direction, which also spaces the knife arms 76 farther apart. Each of first and second sickle drives 62C and 62D includes a knife arm 76 atop upper surface 68 of enclosure 64 and extending forwardly therefrom. Knife arms 76 pivotally connect to the knife assemblies in the above described manner, respectively, and are movable by the respective drive 62C or 62D in a sideward pivoting action that will translate via a pivoting relationship into the above described sideward reciprocating movement, as restrained by the guards. Knife arms 76 are the only upwardly externally protruding elements of first and second drives 62C and 62D, the other elements being located within the internal cavity of enclosure 64, to minimize interruption of the plant material flow.

Like with drives 62A and 62B, the internal elements of first and second drives 62C and 62D are disposed in side by side relation in enclosure 64. First and second drives 62C and 62D are each configured as an epicyclic arrangement, including a central rotatable input element, an eccentric element rotatable along an epicyclical orbit about the input element, and a pivoting drive arm moved by the eccentric element to pivot the knife arm in the side to side direction. More particularly, first drive 62C includes a rotatable first input element 82 supported in an upper region of cavity 78 for rotation about a generally upstanding first rotational axis 84. Drive 62C includes a first eccentric element 86 supported in cavity 78 below first input element 82 for rotation thereby in eccentric relation to first rotational axis 84 about a generally upstanding first eccentric axis 88 laterally offset relative to rotational axis 84, such that eccentric element 86 will follow an epicyclical path 90 about rotational axis 84. Drive 62C includes a first drive arm 92 disposed in cavity 78, having a first end 94 and an opposite second end 96. First end 94 is rotatably connected to eccentric element 86 for rotation therewith along epicyclical path 90 about first rotational axis 84. First drive arm 92 extends laterally in a first sideward direction relative to axis 84 from first end 94 to second end 96. Second end 96 pivotally connects to a pivot arm 98 connected eccentrically to a pivot shaft 100 of a first pivot element 102 supported for rotation about a generally upstanding first pivotal axis 104 therethrough. First drive arm 92 can be observed as being largely contained within the horizontal extent of the first input element 82. Pivot shaft 100 extends upwardly through an aperture 106 through upper cover 68 of enclosure 64 and fixedly connects to a knife arm 76, e.g., via a splined connection or the like.

Second drive 62D includes a rotatable second input element 110 supported in an upper region of the cavity of the enclosure for rotation about a generally upstanding second rotational axis 112, beside first input element 82. Drive 62D includes a second eccentric element 114 supported in cavity 78 below second input element 110 for rotation thereby in eccentric relation to second rotational axis 112 about a generally upstanding second eccentric axis 116 laterally offset relative to rotational axis 112, such that eccentric element 114 will follow an epicyclical orbital path 118 about rotational axis 112. Drive 62D includes a second drive arm 120 disposed in cavity 78, having a first end 122 and an opposite second end 124. First end 122 is rotatably connected to second eccentric element 114 for rotation therewith about second eccentric axis 116 in eccentric relation to, and about, second rotational axis 112. Second drive arm 120 extends laterally in a second sideward direction relative to axis 112 from first end 122 to second end 124. Second end 124 pivotally connects to a pivot arm 126 connected eccentrically to a pivot shaft 128 of a second pivot element 130 supported for rotation about a generally upstanding second pivotal axis 132 therethrough. Second drive arm 120 can be observed as being largely contained within the horizontal extent of the second input element 110. Pivot shaft 128 extends upwardly through an aperture 134 through upper cover 68 of enclosure 64 and fixedly connects to a second knife arm 76, again via a splined connection or the like. Second drive 62D will essentially be a mirror image of first drive 62C.

As with drives 62A and 62B, eccentric elements 86 and 114 of drives 62C and 62D are fixedly connected to the respective input elements 82 and 110 for rotation therewith. Drive arms 92 and 120 are compactly mounted about the respective eccentric elements 86 and 114 via bearings for rotation thereabout, the eccentric elements and drive arms being held vertically together by threaded fasteners or the like. The opposite ends of arms 92 and 120 connect to pivot arms 98 and 126 via pivot joints 150 which can also include bearings to allow relative rotation or pivoting action. Pivot shafts 100 and 128 are supported for rotation in apertures 106 and 134, respectively, by bearings 152. To rotate input elements 82 and 110 of drives 62C and 62D, a rotatable power source 142 is provided, which is preferably an electric or fluid motor, located largely in the overall vertical profile of the drive connected in driving relation to one of the input elements 82 or 110 via a gear arrangement 144 or the like. In operation, referring to drive 62D, the eccentric movements of first end 122 of drive arm 120 along the epicyclic path 118 resulting from rotation of input element 110 (arrow R) will translate into pivotal movements of second end 124 of the drive arm, pivot element 130 and knife arm 76 along arcuate path 136. This will result in the attached knife assembly being reciprocatingly moved in the same manner as described above.

As an advantage of the invention, because the two drives are oppositely moving, external forces and resulting vibrations generated by the drives in both the sideward and fore and aft directions, are largely canceled. As another advantage, the configuration of drives 62A-D, and packaging in a single enclosure 64, allows pivot shafts 100 and 128, and also the pivotal connections between the drive arms and pivot arms, to be of relatively large diameter, and the drive arms to be relatively short and light weight, so as to be robust and strong while the drives are compact, both vertically, and horizontally.

Here, it should be understood that according to the invention it is contemplated that the arrangement of elements of drives 62A and 62B can be vertically reversed, such that the input element is on the bottom, if desired or required for a particular application.

In light of all the foregoing, it should thus be apparent to those skilled in the art that there has been shown and described a pivoting action low profile sickle drive. However, it should also be apparent that, within the principles and scope of the invention, many changes are possible and contemplated, including in the details, materials, and arrangements of parts which have been described and illustrated to explain the nature of the invention. Thus, while the foregoing description and discussion addresses certain preferred embodiments or elements of the invention, it should further be understood that concepts of the invention, as based upon the foregoing description and discussion, may be readily incorporated into or employed in other embodiments and constructions without departing from the scope of the invention. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown, and all changes, modifications, variations, and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention, which is limited only by the claims which follow. 

What is claimed is:
 1. A sickle drive for a plant cutting machine having a first sickle knife assembly supported for side to side reciprocating movement along a forward end of a floor of the machine, a first knife arm connected in driving relation to the first sickle knife assembly, and a rotary power source for driving the knife arm, the sickle drive comprising: a disk-shaped first input element supported for rotation about a generally upstanding first rotational axis and configured for connection in rotationally driven relation to the rotary power source; a first eccentric element connected to the first input element for rotation eccentrically about the first rotational axis; a first pivot element disposed beside the first input element and supported for rotation about a generally upstanding first pivotal axis; and a first drive arm configured for being in generally horizontally coextensive relation with the first input element, the first drive arm having a first end connected to the first eccentric element for rotation therewith eccentrically about the first rotational axis, the first drive arm further having a second end providing a pivotal connection with the first pivot element within an outer circumference of the first input element, wherein the first pivot element comprises a first pivot arm extending eccentrically relative to the first pivotal axis to the pivotal connection with the first drive arm such that the eccentric rotation of the first eccentric element causes the first drive arm to reciprocatingly pivot the first pivot element about the first pivotal axis, and wherein the first pivot element is configured for connecting to the first knife arm such that the pivotal movement of the first pivot element is configured for reciprocatingly moving the first sickle knife assembly along its longitudinal axis.
 2. The sickle drive of claim 1, wherein the drive further comprises: a disk-shaped second input element supported beside the first input element for rotation about a generally upstanding second rotational axis and configured for connection in rotationally driven relation to the rotary power source; a second eccentric element connected to the second input element for rotation eccentrically about the second rotational axis; a second pivot element disposed beside the second input element and supported for rotation about a generally upstanding second pivotal axis; and a second drive arm configured for being in generally horizontally coextensive relation with the second input element, the second drive arm having a first end connected to the second eccentric element for rotation therewith eccentrically about the second rotational axis, the second drive arm further having a second end providing a pivotal connection with the second pivot element within an outer circumference of the second input element, wherein the second pivot element comprises a second pivot arm extending eccentrically relative to the second pivotal axis to the pivotal connection with the second drive arm such that the eccentric rotation of the second eccentric element causes the second drive arm to reciprocatingly pivot the second pivot element about the second pivotal axis, and wherein the second pivot element is configured for connecting to a second knife arm of the machine such that the pivotal movement of the second pivot element is configured for reciprocatingly moving a second sickle knife assembly of the machine along its longitudinal axis.
 3. The sickle drive of claim 2, wherein the first input element and the second input element are connected together for joint rotation in opposite rotational directions for reciprocatingly moving the first and second sickle knife assemblies along their respective longitudinal axes in opposite directions.
 4. The sickle drive of claim 1, wherein the first input element is configured to be connected to a rotatable power source.
 5. The sickle drive of claim 1, wherein the sickle drive is configured to be disposed within a cover incorporated in or beneath the floor of the machine.
 6. The sickle drive of claim 5, wherein the sickle drive is configured to be disposed between opposite side ends of a header of the machine.
 7. A low profile sickle drive comprising; commonly driven, disk shaped first and second input elements supported in generally parallel vertically coextensive relation, for rotation about a generally upstanding first rotational axis and a generally upstanding second rotational axis, respectively; a first pivot element disposed beside the first input element, the first pivot element comprising a first pivot shaft supported for rotation about a generally upstanding first pivotal axis through the first pivot shaft; a first drive arm having a first end and an opposite second end, the first end connected to the first input element for eccentric rotation along an epicyclical path about the first rotational axis, the first drive arm extending laterally relative to the first rotational axis to the second end, the second end pivotally connecting to the first pivot element within an outer circumference of the first input element, such that the eccentric rotation of the first end of the first drive arm causes the first drive arm to reciprocatingly pivot the first pivot element about the first pivotal axis; and a first knife arm mounted on the first pivot shaft and connected to a first sickle knife assembly in a manner such that pivotal movement of the first pivot element reciprocatingly moves the first sickle knife assembly along its longitudinal axis; a second pivot element disposed beside the second input element, the second pivot element comprising a second pivot shaft supported for rotation about a generally upstanding second pivotal axis through the second pivot shaft; a second drive arm having a first end and an opposite second end, the first end of the second drive arm connected to the second input element for eccentric rotation along an epicyclical path about the second rotational axis, the second drive arm extending laterally relative to the second rotational axis to the second end thereof, the second end of the second drive arm pivotally connecting to the second pivot element within an outer circumference of the second input element, such that the eccentric rotation of the first end of the second drive arm causes the second drive arm to reciprocatingly pivot the second pivot element about the second pivotal axis; and a second knife arm mounted on the second pivot shaft and connected to a second sickle knife assembly in a manner such that the pivotal movement of the second pivot element reciprocatingly moves the second sickle knife assembly along its longitudinal axis oppositely of the movement of the first sickle knife assembly, wherein the first pivot element further comprises a first pivot arm extending eccentrically from the first pivot shaft to the pivotal connection to the first drive arm, and wherein the second pivot element further comprises a second pivot arm extending eccentrically from the second pivot shaft to the pivotal connection to the second drive arm.
 8. The sickle drive of claim 7, further comprising a rotatable power source connected in rotatably driving relation to one of the first input element and the second input element.
 9. The sickle drive of claim 8, wherein the power source comprises a motor.
 10. The sickle drive of claim 9, wherein the motor is a fluid motor.
 11. The sickle drive of claim 9, wherein the motor is an electric motor.
 12. The sickle drive of claim 9, wherein the motor is oriented at an acute angle relative to a direction perpendicular to the longitudinal axis of the first or second sickle knife assembly.
 13. The sickle drive of claim 7, wherein the drive is configured to be disposed completely below a floor of a header.
 14. The sickle drive of claim 13, wherein the drive is configured to be disposed between opposite side ends of the header. 